Control system



H. D. JAMES CONTROL SYSTEM Oct. 14 1924.

Filed April 18, 1919 .VAIWA I.

INVENTOR WITNESSES:

ATTORNEY To all whom it may concern:

Patented Oct. 14, 1924.

UNITED STATES 1,511,341 PATENT OFFICE.

HENRY D. JAMES, 'OF EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING VANIA.

COMPANY, 1 conronarron or PENNSYL- CONTROL SYSTEM.

Application filed April 18, 1919. Serial NO. 290,967.

Be it known that I, HENRY D. JAMES, a citizen of the United States, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Control Systems, of which the following is a specification.

My invention relates to motor-control systems and particularly to systems for controlling drilling-tool motors.

The operations of drilling and pumping oil wells are so dissimilar as'to require the employment of motors of different power and characteristics. In drilling, the object is to strike as hard a blow as possible with the falling drilling tool. In order that the inertia of the electric motor may not retard the falling of the tool, the motor should be accelerated during the falling operation. During the raising of the tool, on the other hand, the motor speed should be slower and the torque greater. In view of the peculiar requirements of drilling-tool motors, therefore, separate equipments have been em ployed for pumping and for drilling, the drilling equipment being moved from place to place and the permanently installed, following the drilling operation. I

The object of my invention is to provide a motor-control system whereby the same motors which are employed for pumping may be employed also for drilling.

According to my invention, two standard motors, either of which may later be employed for pumping purposes and both of which may later be employed for more hea work, such as is occasionally found desirable in connection with oil wells, are connected in cascade during drilling. The motors are thus operated at slow speed during such time as the drilling tool is being lifted. Upon the tool reaching its maximum height, a master switch is operated to short-circuit the cascade-connected motor, leaving the other motor alone in control of the tool, which motor will accordingly operate at increased speed during the falling operation. Upon the tool reaching its lower limit of travel, the motors will again become connected in cascade so as to yield a strong pulling efiect at slow speed.

My invention will be described in connection with the accompanying drawings in pumping equipment being 7 lowering of the according to my invention.

The drilling tool 1 is connected, by a cable 2, to a walking beam 3, which is operated through a crank 4 that is rotatable with a wheel 5 which is connected, by a belt 6, to a countershaft apparatus 7 that is operable by a pair of motors 8 and 9. The motors 8 and 9 are, for convenience, shown as mounted upon the same shaft, structional form is by no my invention. The wheel 5 is provided with a cam 10 upon substantially one-half of its periphery, which cam is adapted to operate a switch 11 for closing the circuit of an actuating coil 12 of a switch 13. The cam 10 is designed to effect the opening of the switch 11 when the crank 4. is in its uppermost position, corresponding to the lowermost position of the drilling tool and toy effect the closing of the switch 11 when in its lowermost position, corresponding to the uppermost position of the drilling tool 1.

The motor 8 is provided with a primary winding 14 and a secondary winding 15, and the motor 9 with a primary winding 16 and a secondary winding 17. Resistors 18 are connected in circuit with the secondary winding 15, and resistors 19 in circuit with the secondary winding 17. The primary winding 16 of the motor!) is connected in circuit with the secondary winding 15 of the motor 8 but is adapted to be short-circuited by the switch 13 during such time as the drilling tool 1 is being lifted.

The motors 8 and 9 o erate the crank 4, through the above-descrili efl'ect the operation of the walking beam 3, which, in turn, effects the lifting and the drilling tool 1 through the cable 2, which is secured to the walking beam 3. When the crank 4 occupies the dotted-line position of Fig. 1, the drilling tool 1 has reached its lowermost position, in which it should strike with a maximum force. At this moment, the switch 11 will be opened by the cam 10 to efi'ect the deenergization of thecoil 12 and the consequent opening of the switch 13.. The motors 8 and 9 will thereupon become connected in cascade so as to o crate at slow speed.

The drilling tool 1 wi thereby be lifted,

though this conmeans essential to ed connections, to

predetermined position,

following its rebound, at the desired slow speed, the cascade connected motors, at that tlme, exerting their maximum torque. The speed and the torque may be controlled by the resistors 18' and 19. Upon the crank 14 reaching its lowermost position, 180 away from that indicated in dotted lines, the drilling tool 1 will have reached its uppermost position and the switch 11 will become released from engagement with the cam 10 to permit its being reclosed, as by means of a spring. The switch 13 will thereupon become closed to effect the short-circuiting of the primary winding 16 of the motor 9. The motor 8 will then alone be connected to the'source of energy so that it will operate at maximum speed, thereby efiecting the operation of the crank 4: at increased speed so as to prevent the drilling tool 1 being held back by the inertia of the moving parts. The speed of the motor 8 may be controlledby the resistor 18.

Following the drilling operation, the motors 8 and 9 may be employed singly for pumping purposes or in parallel for more heavy work.

Modifications will occur to those skilled in the art and are intended to be covered by the appended claims.

I claim as my invention:

1. The combination with a tool and a pair of motors for operating the same, each hav-' ing a primary winding and a seconda winding, of means for connecting the pr1- mary winding of one of said motors in err-- cuit with the secondary winding of the other of said motors when said tool occupies a and means for shortcircuiting said primary winding when said tool occupies a second predetermined position.

2. The combination with a drilling tool, a wheel for operating the same, and a pair of induction motors for rotating ,said wheel, each of said motors havin a primary winding and a secondary win ing, of means for connecting the primary winding of one of, said motors in circuit with the secondary winding of the other. of said motors when said tool is being lifted, a switch for shortcircuiting said rimary winding, and a cam carried by sai wheel for operating said switch upon said tool reaching the end of its upward movement.

3. In an oil-well drilling system, the com-. bination with a drilling tool and electric driving means therefor, of means for auto-. matically accelerating the driving means when the tool begins to drop.

4. In an oil-well drilling system, the combination with a drilling tool and electric driving means therefor, of means for automatically accelerating the drivin means when the tool beg ns to drop and or slowing down the driving means when the tool starts to rise.

5. In a control system, the combination with a plurality of induction motors connected in cascade relation and adapted to drive a common load, of means for automatically short-circuiting the secondary of the first of the cascaded motors for a certain operating period.

6. In a control system, the combination with a'plurality of induction motors connected in .cascade relation and adapted to .drive a common load, of means for perlodically 'short-circuitin the secondary of the first of the cascade motors.

7. In a control system, the combination with a plurality of motors adapted to drive a common load, of means for automatically changing and restoring certain operating characteristics of a portion of said motors for predetermined relative eriods.

8. In a control system, t e combination with a plurality of motors adapted to drive a common load,'of means for automatically changing and restoring the speed-torqi1e characteristics of a ortion of said motors for predetermined re ative periods- 9. In a control system, the combination with a plurality of motors adapted to drive a common load, of means for automatically changing and restoring the speed-torque characteristics of a ortion of said motors for periods respectively corresponding to.

substantially equal movements of the 10a 10. In an oil-well drilling system, the combination with a drilling tool and electric drivin means therefor, of means for automatica accelerating said driving means during t e down stroke of the tool and slowing dow'n said driving means during the up stroke of the tool.

11. In a control system, the combination with a plurality of induction motors connected in cascade relation and adapted to drive a common load, of means for automatically increasing and decreasi'ng the excitation of the motors for predetermined relative operating periods.

12. In a control system, the combination with a plurality of induction motors connected in cascade relation and adapted to drive a common load, of means for automatically increasing and decreasing the excitation of the motors for periods respectively corresponding to substantially equal movements of the load.

13. In an oil-well drilling system, combination witlra drilling tool and dri means therefor comprisin a plurality o induction motors connecte in cascade rela' tion, of means for automatically increasing the and decreasing the excitation of the motors 14. The combination with a drilling tool,

a pluralit of induction motors connecte in casca e relation, of means for rendering one of said t motors operative or inoperative, and cam means carried by said wheel for governing said means.

15. The combination with a drilling tool, a wheel for operating said tool, and drivin means therefor comprising a pluralit of induction motors connected in casca e relation, of switching means for short-circuiting one of said motors or removing the short-circuit therefrom, and cam means actuated 'by said vvheel for governing said g means to apply said short-circuit during the down stroke of the tool short-circuit during the 16. The combination with a drilling tool, and driving means therefor comprising a and remove the up stroke of the pair of induction motors connected in cascade relation, of switching means responsive g to the position of said tool for short-circuiting the second motor in the cascade train.

In testimony whereof, I have hereunto subscribed my name this 31st day of March,

HENRY D. J AMES; 

